BANGKOK, Jan. 2 (UPI) -- Thai authorities say most of the bombs that exploded across Bangkok on New Year's Eve were primarily made from ammonium nitrate.
Police spokesman Gen. Achirawit Suphanphesat said they were small -- about 5 inches by 3 inches -- and were set off by digital clocks, The Bangkok Post reported Tuesday.
A total of eight bombs exploded on New Year's Eve, killing three people and injuring 38 others, including two Serbian nationals, two Britons, one Hungarian and one American.
Seven explosions occurred in Bangkok and one in neighboring Nonthaburi province.
No group has definitively been identified as responsible for the blasts, but Prime Minister Surayud Chulanont has blamed the incidents on supporters of former Prime Minister Thaksin Shinawatra, who was toppled in a military coup earlier in the year.
"Based on various reports of intelligence agencies and evidence available, it was the work of people who lost political benefits, but I cannot clearly say which particular group was behind it," Surayud said at a news conference.
Security has been boosted in Bangkok, especially around tourist venues, as well as in Phuket and Chiang Mai, popular tourist destinations outside the capital.
The chemical is commonly used in fertilizer.
